Fans arrived as early as 4 a.m. to catch a glimpse of Daniel Radcliffe, Emma Watson, Rupert Grint and others, and each star made sure to greet the onlookers, signing posters and posing for pictures, before stepping in front of the flashing lights and outstretched microphones on the carpet itself.

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“It’s like traveling with the Beatles,” director David Yates told MTV News.

The sixth film in J.K. Rowling’s boy-wizard series, “Half-Blood Prince” sees the students at Hogwarts growing up and beginning to deal with romantic impulses, heated entreaties and painful rejections. For the stars, who’ve been working together since they were young kids on 2001’s “Harry Potter and the Philosopher’s Stone,” the need to film “snogging” scenes, as those Brits put it, made for some uncomfortable moments on the set.

“I’ve known Bonnie [Wright, who plays Ginny Weasley] — even though she’s obviously stunningly beautiful, as you have seen tonight — I’ve known her since she was 9 and I was 11,” Radcliffe said. “So that was kind of weird at first. But we got used to it. We got over it pretty quickly.”

Watson seconded that opinion. “It was really awkward. Rupert’s like my brother, so it just felt very, very strange,” she admitted. “But he’s a gentleman, and he was a great kisser.”

Joining Radcliffe and Watson under the city lights and in the middle of the “Potter” madness were their co-stars. Wright, with her red hair swept up high and clipped in the back, spoke to us about her unnerving make-out scenes and her fantastic Quidditch matches. Freddie Stroma, making his debut in the film franchise, complimented his castmates for welcoming him into the fold. Michael Gambon, Alan Rickman and Warwick Davis also made appearances.